RawGI Pass Problems

[fewlo]

Hello all,

I'm trying to produce a 'build-up' animation using animation(rendering) as per the online tutorial. I've done this plenty of times in the past but this is the first using HDRI Dome Light as my main light, and I'm having all sorts of problems with it! Please take a look at this vid of the rawGI pass:

http://www.youtube.com/watch?v=Ng8fW...ature=youtu.be

As well as the horrendous splotches, dancing, colour blobs etc, the render times are through the roof, around 2hrs a frame, where realistically for the scene and our hardware I'd expect around 20-25mins.

Imap calculated with med anim preset Hsph 70 Interp 35 then dropped to Hsph 70 Interp 5 for the renders.

I'd appreciate some help on why I'm getting these problems, the footage I've rendered using usuals precalced map every 10 frames looks fine...

Thanks, Michael.

[Morbid Angel]

hmm you say you did this before using the same method no problem? I can't see this working using pre-calculated IR map at all. Since you have everything moving, camera, objects etc, there will be no way to precalculate and interpolate IR map. Just use brute force with light cache it will be faster/better for this particular situation.

[fewlo]

No I meant I'd done other footage with the same lighting conditions, only the camera moving, so used the med anim settings calculated every 10th frame, the footage in my clip is animation(prepass) & animation(render) every frame.

Thanks for the advice though, I'll try bf and lc, I've never dared try that combo for fear of silly render times, but now seems as good a time as any to try!

[Morbid Angel]

Thanks for the advice though, I'll try bf and lc, I've never dared try that combo for fear of silly render times, but now seems as good a time as any to try!

Yes, the thing is, for brute force and exterior especially when you are using dome light, its much favored approach for how good the result you get and the time you spend setting it up. If you were in the interior, this would be different, since a lot of bounce/detail will be needed to compute by brute force gi. On the exterior though, all the primary rays are calculated by the dome light (direct) and the bounce is what brute force/lc are calculating and since there isnt much bounce to calculate it much faster.

[fewlo]

Great, I look forward to trying this out in the morning. Will default bf settings be an ok starting point?

[Morbid Angel]

Will default bf settings be an ok starting point?

bf is tied with dmc sampler, depending on your overall settings, you may need to raise the subdivs. See how much noise you are getting, I usually start from default and work my way from there.

[Neilg]

You could probably do that kind of shot without GI too. Drop the sky/hdri in a domelight, switch GI off.

I find the animation modes in the IR map unbelievably slow on full frames, and by the time you've got a clean result your render time is so high to make it kind of pointless. I think it's only supposed to be used in vray sphere fades and separate passes rather than full frames.

[fewlo]

Thanks cg I'll try this later in the week as another test, thank goodness I haven't got a usual silly deadline on this one! I've been playing with bf settings as morbid suggested and I'm almost happy with the noise/render time ratio, but it could be better.

[fewlo]

Hi guys,

Just wanted to say thank you for your help on this matter, in the end I used both your techniques for various different cameras that made up the final animation. It was really interesting exploring using bf, as I earlier mentioned I'd never dare do it for fear of daft render times. My render times were still relatively high in the end (about 45mins), and there was a level of noise which will be fine with the client but borderline acceptable to me, but I guess this can be made better with more testing. The key problems of my original post were cleared up though so that was great.